U.S. patent number 10,471,789 [Application Number 15/559,224] was granted by the patent office on 2019-11-12 for suspension device.
This patent grant is currently assigned to Honda Motor Co., Ltd.. The grantee listed for this patent is HONDA MOTOR CO., LTD.. Invention is credited to Kosuke Matsushita.
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United States Patent |
10,471,789 |
Matsushita |
November 12, 2019 |
Suspension device
Abstract
Provided is a semi-trailing suspension device including: a
trailing arm that is coupled to a vehicle body in a turnable
manner; a trailing bush that is provided between the vehicle body
and the trailing arm and pivotally supports the trailing arm in a
turnable manner; a lower arm that is coupled to the vehicle body in
a turnable manner; a lower arm bush that is provided between the
vehicle body and the lower arm and pivotally supports the lower arm
in a turnable manner; and a hinge mechanism that couples the
trailing arm and the lower arm to each other in a relatively
displaceable manner.
Inventors: |
Matsushita; Kosuke (Wako,
JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
HONDA MOTOR CO., LTD. |
Minato-Ku, Tokyo |
N/A |
JP |
|
|
Assignee: |
Honda Motor Co., Ltd. (Tokyo,
JP)
|
Family
ID: |
56920049 |
Appl.
No.: |
15/559,224 |
Filed: |
March 19, 2015 |
PCT
Filed: |
March 19, 2015 |
PCT No.: |
PCT/JP2015/058177 |
371(c)(1),(2),(4) Date: |
September 18, 2017 |
PCT
Pub. No.: |
WO2016/147371 |
PCT
Pub. Date: |
September 22, 2016 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20180093541 A1 |
Apr 5, 2018 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B60G
7/02 (20130101); B60G 3/20 (20130101); B60G
7/008 (20130101); B60G 7/001 (20130101); B60G
2204/143 (20130101); B60G 2204/41 (20130101); B60G
2204/148 (20130101) |
Current International
Class: |
B60G
7/00 (20060101); B60G 3/20 (20060101); B60G
7/02 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
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|
|
|
|
10 2010 029 032 |
|
Nov 2011 |
|
DE |
|
0 691 225 |
|
Dec 1999 |
|
EP |
|
S52-37649 |
|
Sep 1977 |
|
JP |
|
S58-192109 |
|
Dec 1983 |
|
JP |
|
S60-33111 |
|
Feb 1985 |
|
JP |
|
2006-321376 |
|
Nov 2006 |
|
JP |
|
2008-018924 |
|
Jan 2008 |
|
JP |
|
2008-195296 |
|
Aug 2008 |
|
JP |
|
2013-509325 |
|
Mar 2013 |
|
JP |
|
Other References
Office Action dated May 8, 2018 issued in the corresponding
Japanese Patent Application 2017-505967 with the English
translation therof. cited by applicant .
Office Action dated Jan. 8, 2019 issued in the counterpart Japanese
Patent Application 2017-505967 and the English translation thereof.
cited by applicant.
|
Primary Examiner: Brown; Drew J
Attorney, Agent or Firm: Carrier Blackman & Associates,
P.C. Carrier; Joseph P. Gedeon; Jeffrey T.
Claims
The invention claimed is:
1. A semi-trailing suspension device comprising: a trailing arm
that is coupled to a vehicle body in a turnable manner; a trailing
bush that is provided between the vehicle body and the trailing arm
and pivotally supports the trailing arm in a turnable manner; a
lower arm that is coupled to the vehicle body in a turnable manner;
a lower arm bush that is provided between the vehicle body and the
lower arm and pivotally supports the lower arm in a turnable
manner; and a hinge mechanism that couples the trailing arm and the
lower arm to each other in a relatively displaceable manner,
wherein the hinge mechanism is provided with an upper bush disposed
on an upper side and a lower bush disposed on a lower side, the
upper bush and the lower bush respectively include an inner
cylindrical member, and outer cylindrical member that is disposed
on the outer diameter side of the inner cylindrical member, a
rubber elastic body provided between the inner cylindrical member
and the outer cylindrical member, and a bolt that passes through
the inner cylindrical member, the upper bush has a void section on
a virtual line connecting an input load and a center point of the
bolt in the rubber elastic body, the lower bush has a void section
on a line other than a virtual line connecting an input load and a
center point of the bolt, the upper bush and the lower bush are
made of the same bush, and a stiffness along the virtual line
connecting the input load and the center point of the bolt of the
upper bush is lower than that along the virtual line connecting the
input load and the center point of the bolt of the lower bush.
2. The semi-trailing suspension device according to claim 1,
wherein the upper bush and the lower bush have rubber elastic
bodies respectively, and the rubber elastic body of the upper bush
is made of a soft rubber, and the rubber elastic body of the lower
bush is made of a hard rubber.
Description
TECHNICAL FIELD
The present invention relates to semi-trailing suspension
devices.
BACKGROUND ART
For example, Patent Literature 1 discloses a semi-trailing
suspension device 3 that is divided in advance into a trailing arm
1 and a lower arm (one piece arm) 2 as shown in FIG. 9A. In the
suspension device 3, a vehicle rear side end 1a of the trailing arm
1 and a vehicle width direction outer end 2a of the lower arm 2 are
hinge-coupled by two rubber bushes 4a, 4b.
A vehicle front side end 1b of the trailing arm 1 is attached to a
vehicle body via a trailing bush 5 in a turnable manner. A vehicle
width direction inner end 2b of the lower arm 2 is attached to the
vehicle body via a trailing bush 6 in a turnable manner. In this
case, a semi-trailing axis A1 (see dotted and dashed thin line)
with respect to the vehicle body is formed by connecting a turning
center point C1 of the trailing arm 1 to a turning center point C2
of the lower arm 2 with each other.
CITATION LIST
Patent Literature
Patent Literature 1: EP0691225B1
SUMMARY OF INVENTION
Technical Problem
In general, in a semi-trailing suspension device including a
suspension device 3 disclosed in Patent Literature 1, camber
characteristics at the time of a suspension stroke (i.e., a
relationship between a suspension stroke quantity in the vertical
direction and a camber angle) is determined by the semi-trailing
axis A1.
FIG. 9B is a characteristic diagram showing a relationship between
a suspension stroke quantity and a camber angle (i.e., camber
characteristics) in the suspension device 3. From FIG. 9B, a camber
characteristics line E1 needed for the semi-trailing axis A1 can be
obtained. In addition, the camber angle means an inclination angle
of a tire in a front view of the vehicle. If an upper portion of
the tire inclines outwardly, it is called a positive camber. If the
upper portion of the tire inclines inwardly, it is called a
negative camber.
In fact, however, a spare tire pan for housing a spare tire, a
layout space 7 for a differential mechanism in a 4-Wheel-Drive
(4WD) vehicle, etc. are necessary (see FIG. 10A). In order to avoid
any interference (contact) between the layout space 7 and the
suspension device 3, an inclined angle (an arrangement angle) of
the lower arm 2 relative to the vehicle body may be changed.
The semi-trailing axis A1 is moved in accordance with the change of
the inclined angle of the lower arm 2 (see dotted and dashed bold
line). Due to the movement of the semi-trailing axis A1, an actual
camber characteristics line E2 (see dashed line) set by the layout
space 7 is decreased to be lower than the preliminarily required
camber characteristics line E1 (i.e., camber angle) (see FIG. 10B).
As a result, compared to the required camber characteristics line
E1, it is difficult for the actual camber characteristics line E2
set by the layout space 7 to obtain a large camber angle
corresponding to an increase in the suspension stroke quantity.
An object of the present invention is to provide a suspension
device which can avoid decrease in the camber characteristics while
keeping a desired layout space.
Solution to Problem
For achieving the above object, according to one aspect of the
present invention, a semi-trailing suspension device includes: a
trailing arm that is coupled to a vehicle body in a turnable
manner; a trailing bush that is provided between the vehicle body
and the trailing arm and pivotally supports the trailing arm in a
turnable manner; a lower arm that is coupled to the vehicle body in
a turnable manner; a lower arm bush that is provided between the
vehicle body and the lower arm and pivotally supports the lower arm
in a turnable manner; and a hinge mechanism that couples the
trailing arm and the lower arm to each other in a manner allowing
relative displacement, in which the hinge mechanism is provided
with an upper bush disposed on an upper side and a lower bush
disposed on a lower side, and a stiffness of the upper bush is
lower than that of the lower bush.
According to the present invention, the stiffness of the upper bush
is lower than that of the lower bush. For example, when a lateral
force is applied as an input load, the lower bush having higher
stiffness than that of the upper bush can support a component force
caused by the lateral force and keep suspension stiffness at high.
Further, according to the present invention, when a suspension
stroke in vertical direction is applied as the input load, the
upper bush having lower stiffness than that of the lower bush moves
toward a vehicle width direction inner side, the camber angle of
the tire can be made large, and large camber characteristics can be
obtained.
In addition, according to the present invention, the upper bush and
the lower bush have rubber elastic bodies respectively. The rubber
elastic body of the upper bush is made of a soft rubber, and the
rubber elastic body of the lower bush is made of a hard rubber.
According to the present invention, the upper bush and the lower
bush having different stiffnesses can be made easily by using soft
and hard rubbers having different hardnesses (elastic forces).
Advantageous Effects of Invention
In the present invention, a suspension device which can avoid
decrease in camber characteristics while keeping a desired layout
space can be obtained.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a bottom plan view of a state where a suspension device
according to an embodiment of the present invention is applied
respectively to a left rear wheel and a right rear wheel, as viewed
from right below a vehicle;
FIG. 2 is an exploded perspective view of the suspension device
shown in FIG. 1;
FIG. 3 is a bottom view of the suspension device shown in FIG. 1 as
viewed from right below;
FIG. 4 is a side view of the suspension device shown in FIG. 1 as
viewed in a diagonal direction from the vehicle rear side;
FIG. 5A is a sectional view of a bush according to a first example
taken along the line of an axis;
FIG. 5B is a sectional view of a bush according to a second example
taken along the line of an axis;
FIG. 6A is a schematic diagram showing a supported situation of the
suspension device shown in FIG. 1 when a lateral force is applied
to the suspension device;
FIG. 6B is a schematic diagram showing a supported situation of the
suspension device shown in FIG. 1 when a suspension stroke is
applied to the suspension device;
FIG. 7A is a top plan view showing a relationship between the
suspension device and a layout space according to the present
embodiment;
FIG. 7B is a characteristic diagram showing a relationship between
a suspension stroke quantity of the suspension device and a camber
angle according to the present embodiment;
FIGS. 8A-8C are sectional views showing upper bush and the lower
bush having different stiffnesses;
FIG. 9A is a top view of a suspension device of prior art;
FIG. 9B is a characteristic diagram showing relationship between a
suspension stroke quantity and a camber angle of the suspension
device shown in FIG. 9A;
FIG. 10A is a top view showing a situation in which a semi-trailing
axis of the suspension device of prior art is moved in the relation
to the layout space; and
FIG. 10B is a characteristic diagram showing a relationship between
a suspension stroke quantity and a camber angle of the suspension
device shown in FIG. 10A.
DESCRIPTION OF EMBODIMENTS
Hereinafter, embodiments of the present invention are described in
detail with reference to the accompanying drawings as appropriate.
FIG. 1 is a bottom plan view of a state where a suspension device
according to an embodiment of the present invention is applied
respectively to a left rear wheel and a right rear wheel, as viewed
from right below a vehicle. FIG. 2 is an exploded perspective view
of the suspension device shown in FIG. 1. FIG. 3 is a bottom plan
view of the suspension device shown in FIG. 1 as viewed from right
below thereof. FIG. 4 is a side view of the suspension device shown
in FIG. 1 as viewed in a diagonal direction from the vehicle rear
side. In the figures, "front and rear" indicates the vehicle
front-rear direction, "left and right" indicates the vehicle width
direction (left-right direction), and "upper and lower" indicates
the vehicle upper-lower direction (vertical direction)
respectively.
As shown in FIG. 1, a suspension device 10 is disposed
independently to a left rear wheel 12 and a right rear wheel 12
(hereinafter also referred to as a wheel 12), and is configured as
an independent suspension type rear suspension that supports left
and right rear wheels 12, 12 in a rotatable manner. The right rear
wheel 12 and left rear wheel 12 are disposed such that rear
suspensions 10, 10 of the same configuration are located
symmetrically with each other.
As shown in FIG. 2, the suspension device 10 includes a
semi-trailing suspension including: a trailing arm 16 that
pivotally supports the wheel (left rear wheel) 12 via an axle (not
shown) in a rotatable manner and is coupled to a vehicle body 14 in
a turnable manner; a lower arm 20 that supports a vehicle rear side
of the trailing arm 16; and a hinge mechanism 22 that couples the
trailing arm 16 and lower arm 20 to each other in a relatively
displaceable manner. Further, the suspension device 10 includes a
damper 24 and a spring 26, which are disposed on the lower arm 20
separately.
The trailing arm 16 is located at a rear end in the vehicle
front-rear direction and includes an arm body section 28 provided
with the hinge mechanism 22, and an arm section 30 extending from
the arm body section 28 in the vehicle front-rear direction. A
trailing bush 32 that pivotally supports the trailing arm 16 in a
turnable manner is mounted at the vehicle front side end of the arm
section 30.
As shown in FIGS. 2 and 3, the arm section 30 includes: an L-shaped
bent section 34 that is mounted on the trailing bush 32 and bends
substantially in a L-shape in the bottom view; a linear section 36
that is continuous to the L-shaped bent section 34 and extends
substantially linearly along the vehicle front-rear direction; and
an intersection section 38 that extends from the linear section 36
to the arm body section 28, and extends from the vehicle width
direction inner side toward the vehicle width direction outer side
and intersects with the vehicle front-rear direction in the bottom
view.
The hinge mechanism 22 includes the pair of opposite pieces 40a,
40b provided on the arm body section 28 of the trailing arm 16, the
vehicle width outer end 20a of the lower arm 20, the pair of upper
and lower bushes 44a, 44b mounted on the vehicle width outer ends
20a, 20a of the lower arm 20, and the pair of bolts 48, 48 that
couple the vehicle rear end of the trailing arm 16 and the vehicle
width outer end 20a of the lower arm 20 to each other via the pair
of upper and lower bushes 44a, 44b.
As shown in FIG. 2, the arm body section 28 includes a pair of
opposite pieces 40a, 40b that extend in the vehicle body vertical
direction and face substantially in parallel with each other. The
pair of opposite pieces 40a, 40b protrude substantially inward in
the vehicle width direction respectively, and a bolt insertion hole
42 is formed at the top and bottom thereof.
The lower arm 20 has a vehicle width outer end 20a provided at one
end, an vehicle width inner end 20b provided at another end, and a
lower arm body 20c provided between the vehicle width outer end 20a
and the vehicle width inner end 20b. The vehicle width outer end
20a is provided with an upper support section 43a and a lower
support section 43b which branch from a depression 46 in the
vertical direction.
The upper support section 43a and the lower support section 43b are
provided with through holes respectively. The upper bush 44a and
the lower bush 44b are inserted into the through holes respectively
at a predetermined interval in the vertical direction. The upper
bush 44a and the lower bush 44b are, for example, rubber bushes,
and have different stiffnesses. The stiffness of the upper bush 44a
is lower than that of the lower bush 44b.
That is, the upper bush 44a is made to be softer than the lower
bush 44b, and the lower bush 44b is made to be harder than the
upper bush 44a. In other words, when a predetermined load is
applied to the upper bush 44a and the lower bush 44b, a deformation
quantity of the upper bush 44a is larger than that of the lower
bush 44b.
The depression 46 is formed between the upper bush 44a and the
lower bush 44b, and is curved as viewed from rear of the vehicle.
This depression 46 serves as a punched section, and the lower arm
20 is made to be light in weight.
The lower support section 43b is continuous to a lower arm bottom
section 45 which extends along an axis of the lower arm 20 (see
FIGS. 2 and 3), and is formed at a tip of the lower arm bottom
section 45. As shown in FIG. 2, the upper support section 43a is
provided at a tip of a projecting section 47 which projects upward
obliquely from the lower arm body 20c toward a trailing arm 16. In
this way, a stiffness of the lower support section 43b is higher
than that of the upper support section 43a. As a result, the upper
support section 43a and the lower support section 43b, which
support the upper bush 44a and the lower bush 44b respectively,
have different stiffnesses respectively corresponding to those of
the upper bush 44a and the lower bush 44b.
The trailing arm 16 is coupled to the lower arm 20 in a manner
allowing relative displacement via the upper bush 44a, the lower
bush 44b, and the pair of bolts 48, 48 inserted into the bolt
insertion holes 42, 42 of the pair of opposite pieces 40a, 40b.
The vehicle width inner end 20b of the lower arm 20 is provided
with a lower arm bush 50 that supports the lower arm 20 with
respect to the vehicle body 14 (for example, a cross member, see
FIG. 1) in a turnable manner.
A recess 52 of a composite shape formed by combination of a
substantially circular shape and a triangular shape as viewed from
top is disposed between the vehicle width outer end 20a and the
vehicle width inner end 20b of the lower arm 20 (see FIG. 2). The
recess 52 is provided with the damper 24 that attenuates vibration
transmitted from the wheel 12, and a spring (coil spring) that
exhibits a spring force, separately from each other. The damper 24
is attached to the lower arm 20 in a turnable manner with a rod 53
coupled to the lower arm 20 as the turning center.
As shown in FIG. 4, in the recess 52 (see FIG. 2), the spring 26 is
disposed on the vehicle width outer side, and the damper 24 is
disposed on the vehicle width inner side. In other words, the
damper 24 is disposed deeper into inner side of the vehicle width
direction of the lower arm 20 than the spring 26. Effects of such
arrangements are described later in detail (see FIG. 8B).
Thus, the trailing arm 16 and the lower arm 20 are mounted on the
vehicle body 14 respectively via the trailing bush 32 and the lower
arm bush 50 in a turnable manner. A semi-trailing axis A is formed
by connecting a turning center point O1 of the trailing arm 16 to a
turning center point O2 of the lower arm bush 50 with each other by
an imaginary line. The semi-trailing axis A is a turning axis of
the suspension device 10 with respect to the vehicle body 14.
Next, examples of the upper bush 44a and the lower bush 44b will be
explained.
FIG. 5A is a sectional view of a bush according to a first example
taken along the line of an axis; and FIG. 5B is a sectional view of
a bush according to a second example taken along the line of an
axis.
As shown in FIG. 5A, a bush 49 according to a first example
includes an inner cylindrical member 54, an outer cylindrical
member 56 that is disposed on the outer diameter side of the inner
cylindrical member 54, a rubber elastic body 58 provided between
the inner cylindrical member 54 and the outer cylindrical member
56, and a bolt 48 that passes through the inner cylindrical member
54.
An intermediate sleeve 62 is provided between the inner cylindrical
member 54 and the outer cylindrical member 56. The intermediate
sleeve 62 includes an arc-shaped recess 64 extending in the
circumferential direction. A sealed space section 66 is disposed
between the arc-shaped recess 64 and an inner wall of the outer
cylindrical member 56. The space section 66 functions as a liquid
sealing compliance bush when a liquid (not shown) is sealed.
As indicated by a bush 49a according to a second example of FIG.
5B, the bush is not limited to the liquid sealing type bush. For
example, a bush formed only by a rubber elastic body 58a adhered by
vulcanization adhesion between the inner cylindrical member 54 and
the outer cylindrical member 56 may be used without provision of
the intermediate sleeve 62 and the space section 66.
As shown in FIG. 2, the trailing bush 32 and the lower arm bush 30
are provided with shaft members 60. Flat-plate-shape plate pieces
70, 70 having a pair of mounting holes 69, 69 into which bolts 68,
68 may be inserted are provided on both sides of the shaft member
60 in the axial direction. The trailing bush 32 is attached to the
vehicle body 14 by inserting mounting holes 69, 69 into bolts 68,
68. Also, the trailing bush 32 may be attached to a bracket (not
shown) formed on the vehicle body 14 in a turnable manner by
inserting bolts 68, 68 directly into the inside of the inner
cylindrical member 54, without using the flat-plate-shape plate
pieces 70, 70.
An axis of the shaft member 60 is aligned with the turning axis 32a
of the trailing bush 32. As shown in FIG. 3, the turning axis 32a
of the trailing bush 32 is disposed to be inclined toward the
vehicle body inner rear side as viewed from bottom, with respect to
the semi-trailing axis (imaginary line) A that connects the turning
center point O1 of the trailing arm 16 relative to the vehicle body
14 to the turning center point O2 of the lower arm 20 with each
other.
In this embodiment, the suspension device 10 is shown as viewed
from right bottom of the vehicle body 14. However, when the vehicle
body 14 is viewed from top, the suspension device 10 is depicted in
a position symmetrical to the position of FIG. 3. Therefore, a
point where the turning axis 32a of the trailing bush 32 is
disposed to be inclined toward the vehicle body inner rear side as
viewed from top with respect to the semi-trailing axis (imaginary
line) A is the same as the case where the vehicle body 14 is viewed
from right bottom.
In other words, the turning axis 32a of the trailing bush 32 is on
an axis different from the semi-trailing axis A as viewed from
bottom, and is set to a location turned by a predetermined angle in
the clockwise direction with the turning center point O1 of the
trailing bush 32 as a base point.
An intersection angle .theta. between an imaginary line B that
connects the axle center point O3 of the wheel 12 to the turning
center point O1 of the trailing arm 16 with each other and the
turning axis 32a of the trailing bush 32 is set to be smaller than
or equal to 90 degrees (.theta..ltoreq.90 degrees).
The suspension device 10 according to the present embodiment is
made as described above. Next, advantages thereof will be
explained. FIG. 6A is a schematic diagram showing a supported
situation of the suspension device shown in FIG. 1 when a lateral
force is applied to the suspension device; FIG. 6B is a schematic
diagram showing a supported situation of the suspension device
shown in FIG. 1 when a suspension stroke is applied to the
suspension device; FIG. 7A is a top plan view showing a
relationship between the suspension device and a layout space
according to the present embodiment; and FIG. 7B is a
characteristic diagram showing a relationship between a suspension
stroke quantity of the suspension device and a camber angle
according to the present embodiment.
In the present embodiment, the stiffness of the lower bush 44b is
higher than that of the upper bush 44a. As shown in FIG. 6A, for
example, a lateral force Y is applied as an input load, the lower
bush 44b having higher stiffness than that of the upper bush 44a
can support a large component force F1 (a component force whose
direction is the same as that of the lateral force Y) caused by the
lateral force Y, and keep the suspension stiffness at high. At the
same time, a component force F2 whose direction is opposite to that
of the lateral force Y is applied to the upper bush 44a. Since the
component force F2 is smaller than the component force F1
(F1>F2), the upper bush 44a having lower stiffness than that of
the lower bush 44b can support the component force F2.
In addition, in the present embodiment, the stiffness of the upper
bush 44a is lower than that of the lower bush 44b. As shown in FIG.
6B, for example, when a suspension stroke G is applied in the
vertical direction as an input load, the component force F2 is
applied to the upper bush 44a in a vehicle width inner direction.
In this way, the upper bush 44a having lower stiffness than that of
the lower bush 44b can be displaced toward a vehicle width
direction inner side, a camber angle (a negative camber) of the
wheel 12 is increased, and a large camber characteristics can be
obtained. In addition, the component force F1 is applied to the
lower bush 44b in a vehicle width outer direction by the suspension
stroke G.
As a result, in the present embodiment, if a desired layout space S
is secured, the semi-trailing axis A is not moved (see FIG. 7A). In
contrast to a prior art shown in FIG. 10B, the description in the
camber characteristics can be avoided, and a necessary camber
characteristics line E3 can be obtained (see FIG. 7B).
Next, how to make the upper bush 44a and the lower bush 44b having
different stiffnesses will be explained. FIGS. 8A-8C are sectional
views showing an upper bush and a lower bush having different
stiffnesses. Reference signs in FIGS. 8A-8C correspond to those of
the bushes according to the first and second examples shown in
FIGS. 5A-5C.
As shown in FIG. 8A, the upper bush 44a having low stiffness can be
made by forming a void section 72 on a virtual line L connecting an
input load F and a center point O of the bolt 48 in the rubber
elastic body 58. In contrast, the lower bush 44b having high
stiffness can be made by forming a solid section 74 (not the void
section 72) on the virtual line L connecting the input load F and
the center point O of the bolt 48. In addition, the upper bush 44a
and the lower bush 44b shown in FIG. 8A are made of the same bush.
The stiffness of the upper bush 44a and the lower bush 44b varies
depending on a direction (an angle) of an applied load.
As shown in FIG. 8B, the upper bush 44a and the lower bush 44b are
made of rubber elastic bodies having the same thicknesses. The
rubber elastic body of the upper bush 44a is made of a soft rubber
76a, and the rubber elastic body of the lower bush 44b is made of a
soft rubber 76b. As a result, the upper bush 44a and the lower bush
44b having different stiffnesses can be made easily.
Further, as shown in FIG. 8C, the upper bush 44a and the lower bush
44b are made of the rubber elastic bodies 58 having different
thicknesses (i.e., outer diameters). The elastic force of the upper
bush 44a is different from that of the lower bush 44b (i.e., the
elastic force of the lower bush 44b is higher than that of the
upper bush 44a). As a result, the bushes having different
stiffnesses can be made. That is, a thickness T1 of the rubber
elastic body of the upper bush 44a is made to be thick, and a
deformation quantity of the rubber elastic body 58 is made to be
large. A thickness T2 of the rubber elastic body 58 of the lower
bush 44b is made to be thin (T1>T2), and a deformation quantity
of the rubber elastic body 58 is made to be small. As a result, the
stiffness of the upper bush 44a is different from that of the lower
bush 44b.
In addition, for example, a well know Magneto-rheological Elastomer
(MR elastomer) can be used for the rubber elastic body 58. The
upper bush 44a and the lower bush 44b having different stiffnesses
can be made by applying magnetic field to the MR elastomer so as to
change an apparent elasticity.
REFERENCE SIGN LIST
10 suspension device 12 wheel 14 vehicle body 16 trailing arm 20
lower arm 22 hinge mechanism 24 damper 26 spring 32 trailing bush
32a L-shaped bent section 44a upper bush 44b lower bush 50 lower
arm bush 58 rubber elastic body
* * * * *